These Dyson pre filters fit the vacuum better than original Dyson filters which kept falling out. They form a good hermetic seal. I found that this resulted in a significant increase in vacuum suction. I have since learned that these pre-filters should be changed every six months. So this 6 battery pack is a practical and economical solution to keep your dear Dyson in top condition. I highly recommend this brand. Nicely packaged for easy storage for future filter changes. I don't think they need cleaning. I just change and use a new one in this price range.